Quarterly report pursuant to Section 13 or 15(d)

Document and Entity Information

Document and Entity Information - shares
3 Months Ended
Mar. 31, 2016
May. 02, 2016
Entity Information [Line Items]    
Entity Registrant Name Ameresco, Inc.  
Entity Central Index Key 0001488139  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Document Type 10-Q  
Document Period End Date Mar. 31, 2016  
Document Fiscal Year Focus 2016  
Document Fiscal Period Focus Q1  
Amendment Flag false  
Common Class A    
Entity Information [Line Items]    
Common Stock   28,783,142
Common Class B    
Entity Information [Line Items]    
Common Stock   18,000,000